These instructions describe how you can change the details of an Attendee such as their Dietary Requirements, Badge Label etc then 

Start off by going to your Commerce Dashboard

Click on the Attending Attendees Info tile to see a list of your attendees and their details.

Use the filters to find the person you want to edit and then click on the Edit button next to the Attendee you wish to change.

NOTE: The list of fields for an Attendee is configurable for each project and so the fields show in the screenshot (Badge Label and Dietary Requirement) may not be the same as the fields in your project.  Please contact if you wish to change the fields configured for your Attendees in your project.

Edit the details and click on Save.

The grid will then show you the amended details.